Population genomics of Plasmodium ovale species in sub-Saharan Africa.

Plasmodium ovale curtisi (Poc) and Plasmodium ovale wallikeri (Pow) are relapsing malaria parasites endemic to Africa and Asia that were previously thought to represent a single species. Amid increasing detection of ovale malaria in sub-Saharan Africa, we performed a population genomic study of both species across the continent. We conducted whole-genome sequencing of 25 isolates from Central and East Africa and analyzed them alongside 20 previously published African genomes. Isolates were predominantly monoclonal (43/45), with their genetic similarity aligning with geography. Pow showed lower average nucleotide diversity (1.8×10-4) across the genome compared to Poc (3.0×10-4) (p < 0.0001). Signatures of selective sweeps involving the dihydrofolate reductase gene were found in both species, as were signs of balancing selection at the merozoite surface protein 1 gene. Differences in the nucleotide diversity of Poc and Pow may reflect unique demographic history, even as similar selective forces facilitate their resilience to malaria control interventions.

Immunogenicity of a Birth Dose of Hepatitis B Vaccine in Kinshasa, Democratic Republic of Congo: A Randomised, Controlled Trial.

The WHO recommends hepatitis B birth-dose vaccination (HepB-BD), but it is not routinely given in most sub-Saharan African countries. We aimed to assess the immunogenicity of HepB-BD in addition to the existing hepatitis B vaccine (HepB3) schedule in Kinshasa, Democratic Republic of Congo among HBV-unexposed and HBV-exposed infants. Using an open-label, randomised, controlled design, HBV-unexposed infants were randomised (1:1) to receive the standard HepB3 vaccine series (group U3), or to receive HepB-BD in addition to HepB3 (group U4). A supplemental cohort of HBV-exposed infants (group E4) received HepB-BD and HepB3. We compared the proportion of infants with protective antibodies against HBV (HBV surface antibody ≥ 10 mIU/mL) between groups U3 and U4 and groups U4 and E4 at 12 months of age. Between August 20 and October 9, 2019, we enrolled 281 mother/infant dyads; 88 (31.3%) returned at 12 months. Most infants had protective antibodies against HBV at 12 months: 92.9% (75.7%-98.2%) in group U3, 85.7% (67.5%-94.5%) in group U4 and 96.9% (95% CI: 81.2%-99.6%) in group E4. Trends held in estimates adjusted for loss-to-follow-up (LTFU) and baseline imbalance across groups. In this first randomised trial assessing the addition of HepB-BD to the hepatitis B vaccine schedule in SSA, we found that HBV-unexposed infants who received the 3-dose and 4-dose vaccine series had similar immunogenicity against HBV at 12 months. A high proportion of infants, and notably HBV-exposed infants, had protective antibodies. Though extrapolation of findings may be limited by LTFU, this study adds real-world evidence regarding HepB-BD implementation in sub-Saharan Africa. Trial Registration: ClinicalTrials.gov identifier: NCT03897946.

Changes in hepatitis B vaccine perception in response to the COVID-19 pandemic: Development of the Shift in vaccine confidence (SVC) survey tool.

The COVID-19 pandemic has disrupted access to, adherence to, and perceptions of routine vaccinations. We developed the Shift in Vaccine Confidence (SVC) survey tool to assess the impact of the pandemic on routine vaccinations, with a focus on the HBV vaccine, in Kinshasa, Democratic Republic of Congo (DRC). This study describes the content validation steps we conducted to ensure the survey tool is meaningful to measure changes in vaccine confidence to regular immunization (HBV vaccine) due to the pandemic. Three rounds of stakeholder feedback from a DRC-based study team, content and measurement experts, and study participants allowed us to produce a measure with improved readability and clarity.

Low knowledge about hepatitis B prevention among pregnant women in Kinshasa, Democratic Republic of Congo.

Infants infected perinatally with hepatitis B (HBV) are at the highest risk of developing chronic hepatitis and associated sequelae. Prevention of mother-to-child transmission (PMTCT) of HBV requires improved screening and awareness of the disease. This study evaluated existing HBV knowledge among pregnant mothers (n = 280) enrolled in two HBV studies in urban maternity centers in Kinshasa, Democratic Republic of the Congo. All mothers responded to three knowledge questions upon study enrollment. Baseline levels of knowledge related to HBV transmission, treatment, prevention, and symptoms were low across all participants: 68.8% did not know how HBV was transmitted, 70.7% did not know how to prevent or treat HBV MTCT, and 79.6% did not know signs and symptoms of HBV. Over half of participants responded "I don't know" to all questions. HBV-positive women who participated in both studies (n = 46) were asked the same questions during both studies and showed improved knowledge after screening and treatment, despite no formal educational component in either study (p < 0.001). These findings highlight the need for intensified education initiatives in highly endemic areas to improve PMTCT efforts.

Arresting vertical transmission of hepatitis B virus (AVERT-HBV) in pregnant women and their neonates in the Democratic Republic of the Congo: a feasibility study.

BACKGROUND: Hepatitis B virus (HBV) remains endemic throughout sub-Saharan Africa despite the widespread availability of effective childhood vaccines. In the Democratic Republic of the Congo, HBV treatment and birth-dose vaccination programmes are not established. We, therefore, aimed to evaluate the feasibility and acceptability of adding HBV testing and treatment of pregnant women as well as the birth-dose vaccination of HBV-exposed infants to the HIV prevention of mother-to-child transmission programme infrastructure in the Democratic Republic of the Congo. METHODS: We did a feasibility study in two maternity centres in Kinshasa: Binza and Kingasani. Using the already established HIV prevention of mother-to-child transmission programme at these two maternity centres, we screened pregnant women for HBV infection at routine prenatal care registration. Those who tested positive and had a gestational age of 24 weeks or less were included in this study. Eligible pregnant women with a high viral load (≥200 000 IU/mL or HBeAg positivity, or both) were considered as having HBV of high risk of mother-to-child transmission and initiated on oral tenofovir disoproxil fumarate (300 mg/day) between 28 weeks and 32 weeks of gestation and continued through 12 weeks post partum. All HBV-exposed infants received a birth-dose of monovalent HBV vaccine (Euvax-B Pediatric: Sanofi Pasteur, Seoul, South Korea; 0·5 mL) within 24 h of life. All women were followed up for 24 weeks post partum, when they completed an exit questionnaire that assessed the acceptability of study procedures. The primary outcomes were the feasibility of screening pregnant women to identify those at high risk for HBV mother-to-child transmission and to provide them with antiviral prophylaxis, the feasibility of administrating the birth-dose vaccine to exposed infants, and the acceptability of this prevention programme. This study is registered with ClinicalTrials.gov, NCT03567382. FINDINGS: Between Sept 24, 2018, and Feb 22, 2019, 4016 women were approached and screened. Of these pregnant women, 109 (2·7%) were positive for HBsAg. Of the 109 women, 91 (83%) met the eligibility criteria for participation. However, only data from 90 women-excluding one woman who had a false pregnancy-were included in the study analysis. The median overall age of the enrolled women was 31 years (IQR 25-34) and the median overall gestational age was 19 weeks (15-22). Ten (11%) of 91 women evaluated had high-risk HBV infection. Nine (90%) of the ten pregnant women with high-risk HBV infection received tenofovir disoproxil fumarate and one (10%) refused therapy and withdrew from the study; five (56%) of the nine women achieved viral suppression (ie, <200 000 IU/mL) on tenofovir disoproxil fumarate therapy by the time of delivery and the remaining four (44%) had decreased viral loads from enrolment to delivery. A total of 88 infants were born to the 90 enrolled women. Of the 88 infants, 60 (68%) received a birth-dose vaccine; of these, 46 (77%) received a timely birth-dose vaccine. No cases of HBV mother-to-child transmission were observed. No serious adverse events associated with tenofovir disoproxil fumarate nor with the birth-dose vaccine were reported. Only one (11%) of nine women reported dizziness during the course of tenofovir disoproxil fumarate therapy. The study procedures were considered highly acceptable (>80%) among mothers. INTERPRETATION: Adding HBV screening and treatment of pregnant women and infant birth-dose vaccination to existing HIV prevention of mother-to-child transmission platforms is feasible in countries such as the Democratic Republic of the Congo. Birth-dose vaccination against HBV infection integrated within the current Expanded Programme on Immunisation and HIV prevention of mother-to-child transmission programme could accelerate progress toward HBV elimination in Africa. FUNDING: Gillings Innovation Laboratory award and the National Institutes of Health. TRANSLATIONS: For the French and Lingala translations of the abstract see Supplementary Materials section.

A novel CRISPR-based malaria diagnostic capable of Plasmodium detection, species differentiation, and drug-resistance genotyping.

BACKGROUND: CRISPR-based diagnostics are a new class of highly sensitive and specific assays with multiple applications in infectious disease diagnosis. SHERLOCK, or Specific High-Sensitivity Enzymatic Reporter UnLOCKing, is one such CRISPR-based diagnostic that combines recombinase polymerase pre-amplification, CRISPR-RNA base-pairing, and LwCas13a activity for nucleic acid detection. METHODS: We developed SHERLOCK assays capable of detecting all Plasmodium species known to cause human malaria and species-specific detection of P. vivax and P. falciparum, the species responsible for the majority of malaria cases worldwide. We further tested these assays using a diverse panel of clinical samples from the Democratic Republic of the Congo, Uganda, and Thailand and pools of Anopheles mosquitoes from Thailand. In addition, we developed a prototype SHERLOCK assay capable of detecting the dihydropteroate synthetase (dhps) single nucleotide variant A581G associated with P. falciparum sulfadoxine resistance. FINDINGS: The suite of Plasmodium assays achieved analytical sensitivities ranging from 2•5-18•8 parasites per reaction when tested against laboratory strain genomic DNA. When compared to real-time PCR, the P. falciparum assay achieved 94% sensitivity and 94% specificity during testing of 123 clinical samples. Compared to amplicon-based deep sequencing, the dhps SHERLOCK assay achieved 73% sensitivity and 100% specificity when applied to a panel of 43 clinical samples, with false-negative calls only at lower parasite densities. INTERPRETATION: These novel SHERLOCK assays demonstrate the versatility of CRISPR-based diagnostics and their potential as a new generation of molecular tools for malaria diagnosis and surveillance. FUNDING: National Institutes of Health (T32GM007092, R21AI148579, K24AI134990, R01AI121558, UL1TR002489, P30CA016086).

Analysis of false-negative rapid diagnostic tests for symptomatic malaria in the Democratic Republic of the Congo.

The majority of Plasmodium falciparum malaria diagnoses in Africa are made using rapid diagnostic tests (RDTs) that detect histidine-rich protein 2. Increasing reports of false-negative RDT results due to parasites with deletions of the pfhrp2 and/or pfhrp3 genes (pfhrp2/3) raise concern about existing malaria diagnostic strategies. We previously identified pfhrp2-negative parasites among asymptomatic children in the Democratic Republic of the Congo (DRC), but their impact on diagnosis of symptomatic malaria is unknown. We performed a cross-sectional study of false-negative RDTs in symptomatic subjects in 2017. Parasites were characterized by microscopy; RDT; pfhrp2/3 genotyping and species-specific PCR assays; a bead-based immunoassay for Plasmodium antigens; and/or whole-genome sequencing. Among 3627 symptomatic subjects, 427 (11.8%) had RDT-/microscopy + results. Parasites from eight (0.2%) samples were initially classified as putative pfhrp2/3 deletions by PCR, but antigen testing and whole-genome sequencing confirmed the presence of intact genes. 56.8% of subjects had PCR-confirmed malaria. Non-falciparum co-infection with P. falciparum was common (13.2%). Agreement between PCR and HRP2-based RDTs was satisfactory (Cohen's kappa = 0.66) and superior to microscopy (0.33). Symptomatic malaria due to pfhrp2/3-deleted P. falciparum was not observed. Ongoing HRP2-based RDT use is appropriate for the detection of falciparum malaria in the DRC.

Seroepidemiology of Hepatitis B in the Democratic Republic of the Congo.

Hepatitis B virus (HBV) is endemic throughout Africa, but its prevalence in the Democratic Republic of the Congo (DRC) is incompletely understood. We used dried blood spot (DBS) samples from the 2013 to 2014 Demographic and Health Survey in the DRC to measure the prevalence of HBV using the Abbott ARCHITECT HBV surface antigen (HBsAg) qualitative assay. We then attempted to sequence and genotype HBsAg-positive samples. The weighted national prevalence of HBV was 3.3% (95% CI: 1.8-4.7%), with a prevalence of 2.2% (95% CI: 0.3-4.1%) among children. Hepatitis B virus cases occurred countrywide and across age strata. Genotype E predominated (60%), and we found a unique cluster of genotype A isolates (30%). In conclusion, DBS-based HBsAg testing from a nationally representative survey found that HBV is common and widely distributed among Congolese adults and children. The distribution of cases across ages suggests ongoing transmission and underscores the need for additional interventions to prevent HBV infection.

Effect of individual and community-level bed net usage on malaria prevalence among under-fives in the Democratic Republic of Congo.

BACKGROUND: Understanding the contribution of community-level long-lasting, insecticidal net (LLIN) coverage to malaria control is critical to planning and assessing intervention campaigns. The Democratic Republic of Congo (DRC), which has one of the highest burdens of malaria cases and deaths and has dramatically scaled up LLIN ownership in recent years thus it is an ideal setting to evaluate the effect of individual versus community-level use to prevent malaria among children under the age of 5. RESULTS: Data were derived from the 2013-2014 DRC Demographic and Health Survey. Community-level LLIN usage was significantly associated with protection against malaria, even when individual-level LLIN usage was included in the model. In stratified analysis, higher levels of community LLIN coverage enhanced the protective effect of individual LLIN usage, resulting in lower malaria prevalence among individuals who used a LLIN. A sub-analysis of individual LLIN usage by insecticide type revealed deltamethrin-treated nets were more protective than permethrin-treated nets, suggesting that mosquitoes in the DRC are more susceptible to deltamethrin. CONCLUSIONS: This study examines the effects of individual and community-level LLIN usage in young children in an area of high ITN usage. Individual and community LLIN usage were significantly associated with protection against malaria in children under 5 in the DRC. Importantly, the protective effect of individual LLIN usage against malaria is enhanced when community LLIN coverage is higher, demonstrating the importance of increasing community-level LLIN usage. LLINs treated with deltamethrin were shown to be more protective against malaria than LLINs treated with permethrin. Demographic and Health Surveys are thus a novel and important means of surveillance for insecticide resistance.

Plasmodium falciparum genetic variation of var2csa in the Democratic Republic of the Congo.

BACKGROUND: The Democratic Republic of the Congo (DRC) bears a high burden of malaria, which is exacerbated in pregnant women. The VAR2CSA protein plays a crucial role in pregnancy-associated malaria (PAM), and hence quantifying diversity at the var2csa locus in the DRC is important in understanding the basic epidemiology of PAM, and in developing a robust vaccine against PAM. METHODS: Samples were taken from the 2013-14 Demographic and Health Survey conducted in the DRC, focusing on children under 5 years of age. A short subregion of the var2csa gene was sequenced in 115 spatial clusters, giving country-wide estimates of sequence polymorphism and spatial population structure. RESULTS: Results indicate that var2csa is highly polymorphic, and that diversity is being maintained through balancing selection, however, there is no clear signal of phylogenetic or geographic structure to this diversity. Linear modelling demonstrates that the number of var2csa variants in a cluster correlates directly with cluster prevalence, but not with other epidemiological factors such as urbanicity. CONCLUSIONS: Results suggest that the DRC fits within the global pattern of high var2csa diversity and little genetic differentiation between regions. A broad multivalent VAR2CSA vaccine candidate could benefit from targeting stable regions and common variants to address the substantial genetic diversity.

An Efficient, Large-Scale Survey of Hepatitis C Viremia in the Democratic Republic of the Congo Using Dried Blood Spots.

Background: Efficient viral load testing is needed for hepatitis C (HCV) surveillance and diagnosis. HCV viral load testing using dried blood spots (DBSs), made with a single drop of finger-prick whole blood on filter paper, is a promising alternative to traditional serum- or plasma-based approaches. Methods: We adapted the Abbott Molecular m2000 instrument for high-throughput HCV viremia testing using DBSs with simple specimen processing and applied these methods to estimate the national burden of infection in the Democratic Republic of the Congo (DRC). We tested DBSs collected during the 2013-2014 DRC Demographic and Health Survey, including 1309 adults ≥40 years of age. HCV-positive samples underwent targeted sequencing, genotyping, and phylogenetic analyses. Results: This high-throughput screening approach reliably identified HCV RNA extracted from DBSs prepared using whole blood, with a 95% limit of detection of 1196 (95% confidence interval [CI], 866-2280) IU/mL for individual 6-mm punches and 494 (95% CI, 372-1228) IU/mL for larger 12-mm punches. Fifteen infections were identified among samples from the DRC Demographic and Health Survey; the weighted country-wide prevalence of HCV viremia was 0.9% (95% CI, 0.3%-1.6%) among adults ≥40 years of age and 0.7% (95% CI, .6%-.8%) among human immunodeficiency virus-infected subjects. All successfully genotyped cases were due to genotype 4 infection. Conclusions: DBS-based HCV testing represents a useful tool for the diagnosis and surveillance of HCV viremia and can easily be incorporated into specimen referral systems. Among adults ≥40 years of age in the DRC, 100000-200000 may have active infection and be eligible for treatment.

A deep sequencing approach to estimate Plasmodium falciparum complexity of infection (COI) and explore apical membrane antigen 1 diversity.

BACKGROUND: Humans living in regions with high falciparum malaria transmission intensity harbour multi-strain infections comprised of several genetically distinct malaria haplotypes. The number of distinct malaria parasite haplotypes identified from an infected human host at a given time is referred to as the complexity of infection (COI). In this study, an amplicon-based deep sequencing method targeting the Plasmodium falciparum apical membrane antigen 1 (pfama1) was utilized to (1) investigate the relationship between P. falciparum prevalence and COI, (2) to explore the population genetic structure of P. falciparum parasites from malaria asymptomatic individuals participating in the 2007 Demographic and Health Survey (DHS) in the Democratic Republic of Congo (DRC), and (3) to explore selection pressures on geospatially divergent parasite populations by comparing AMA1 amino acid frequencies in the DRC and Mali. RESULTS: A total of 900 P. falciparum infections across 11 DRC provinces were examined. Deep sequencing of both individuals, for COI analysis, and pools of individuals, to examine population structure, identified 77 unique pfama1 haplotypes. The majority of individual infections (64.5%) contained polyclonal (COI > 1) malaria infections based on the presence of genetically distinct pfama1 haplotypes. A minimal correlation between COI and malaria prevalence as determined by sensitive real-time PCR was identified. Population genetic analyses revealed extensive haplotype diversity, the vast majority of which was shared across the sites. AMA1 amino acid frequencies were similar between parasite populations in the DRC and Mali. CONCLUSIONS: Amplicon-based deep sequencing is a useful tool for the detection of multi-strain infections that can aid in the understanding of antigen heterogeneity of potential malaria vaccine candidates, population genetics of malaria parasites, and factors that influence complex, polyclonal malaria infections. While AMA1 and other diverse markers under balancing selection may perform well for understanding COI, they may offer little geographic or temporal discrimination between parasite populations.

Pfhrp2-Deleted Plasmodium falciparum Parasites in the Democratic Republic of the Congo: A National Cross-sectional Survey.

Background: Rapid diagnostic tests (RDTs) account for more than two-thirds of malaria diagnoses in Africa. Deletions of the Plasmodium falciparum hrp2 (pfhrp2) gene cause false-negative RDT results and have never been investigated on a national level. Spread of pfhrp2-deleted P. falciparum mutants, resistant to detection by HRP2-based RDTs, would represent a serious threat to malaria elimination efforts. Methods: Using a nationally representative cross-sectional study of 7,137 children under five years of age from the Democratic Republic of Congo (DRC), we tested 783 subjects with RDT-/PCR+ results using PCR assays to detect and confirm deletions of the pfhrp2 gene. Spatial and population genetic analyses were employed to examine the distribution and evolution of these parasites. Results: We identified 149 pfhrp2-deleted parasites, representing 6.4% of all P. falciparum infections country-wide (95% confidence interval 5.1-8.0%). Bayesian spatial analyses identified statistically significant clustering of pfhrp2 deletions near Kinshasa and Kivu. Population genetic analysis revealed significant genetic differentiation between wild-type and pfhrp2-deleted parasite populations (GST = .046, p ≤ .00001). Conclusions: Pfhrp2-deleted P. falciparum is a common cause of RDT-/PCR+ malaria among asymptomatic children in the DRC and appears to be clustered within select communities. Surveillance for these deletions is needed, and alternatives to HRP2-specific RDTs may be necessary.

Pooled Amplicon Deep Sequencing of Candidate Plasmodium falciparum Transmission-Blocking Vaccine Antigens.

Polymorphisms within Plasmodium falciparum vaccine candidate antigens have the potential to compromise vaccine efficacy. Understanding the allele frequencies of polymorphisms in critical binding regions of antigens can help in the designing of strain-transcendent vaccines. Here, we adopt a pooled deep-sequencing approach, originally designed to study P. falciparum drug resistance mutations, to study the diversity of two leading transmission-blocking vaccine candidates, Pfs25 and Pfs48/45. We sequenced 329 P. falciparum field isolates from six different geographic regions. Pfs25 showed little diversity, with only one known polymorphism identified in the region associated with binding of transmission-blocking antibodies among our isolates. However, we identified four new mutations among eight non-synonymous mutations within the presumed antibody-binding region of Pfs48/45. Pooled deep sequencing provides a scalable and cost-effective approach for the targeted study of allele frequencies of P. falciparum candidate vaccine antigens.

Spatial and social factors drive anemia in Congolese women.

Anemia is common in women of child-bearing age in the Democratic Republic of the Congo (DRC). As part of the 2007 DRC Demographic and Health Survey (DHS), 4638 women of childbearing age (including 526 pregnant women) were tested for HIV and had the hemoglobin content of their blood recorded. We used the leftover dried blood spots to assess malaria prevalence using PCR assays. The DHS provided extensive information on individuals, as well as the geographic coordinates of household clusters which enabled us to derive several variables that characterize the spatial context of these clusters. Multilevel analyses were conducted to determine individual and contextual risk factors for anemia. Prevalence varied geographically; the odds of anemia were associated with both one's ethnic group and the amount and type of nearby agriculture. The odds were not affected by HIV or malaria status.

Quantification of the burden and consequences of pregnancy-associated malaria in the Democratic Republic of the Congo.

BACKGROUND: Pregnancy-associated malaria (PAM) produces poor birth outcomes, but its prevalence is commonly estimated in convenience samples. METHODS: We assessed the prevalence of malaria using real-time polymerase chain reaction (PCR) and estimated the consequences of infection on birth outcomes, using specimens from a nationally representative sample of 4570 women of childbearing age (WOCBA) responding to the 2007 Demographic and Health Survey in Democratic Republic of the Congo (DRC). RESULTS: Overall, 31.2% (95% confidence interval [CI], 29.2-33.1) of WOCBA were parasitemic, which was significantly more common in pregnant (37.2% [31.0-43.5]) than nonpregnant women (30.4% [CI, 28.4-32.5], prevalence ratio [PR] 1.22 [1.02-1.47]). Plasmodium falciparum was highest among pregnant women (36.6% vs 28.8%, PR 1.27 [1.05-1.53]). By contrast, P malariae was less common in pregnant (0.6%) compared with nonpregnant women (2.7%, PR 0.23 [0.09-0.56]). Extrapolation of the prevalence estimate to the population at risk of malaria in DRC suggests 1.015 million births are affected by P falciparum infection annually, and that adherence to preventive measures could prevent up to 549 000 episodes of pregnancy-associated malaria and 47 000 low-birth-weight births. CONCLUSIONS: Pregnancy-associated malaria and its consequences are highly prevalent in the DRC. Increasing the uptake of malaria preventive measures represents a significant opportunity to improve birth outcomes and neonatal health.

Population, behavioural and environmental drivers of malaria prevalence in the Democratic Republic of Congo.

BACKGROUND: Malaria is highly endemic in the Democratic Republic of Congo (DRC), but the limits and intensity of transmission within the country are unknown. It is important to discern these patterns as well as the drivers which may underlie them in order for effective prevention measures to be carried out. METHODS: By applying high-throughput PCR analyses on leftover dried blood spots from the 2007 Demographic and Health Survey (DHS) for the DRC, prevalence estimates were generated and ecological drivers of malaria were explored using spatial statistical analyses and multilevel modelling. RESULTS: Of the 7,746 respondents, 2268 (29.3%) were parasitaemic; prevalence ranged from 0-82% within geographically-defined survey clusters. Regional variation in these rates was mapped using the inverse-distance weighting spatial interpolation technique. Males were more likely to be parasitaemic than older people or females (p < 0.0001), while wealthier people were at a lower risk (p < 0.001). Increased community use of bed nets (p = 0.001) and community wealth (p < 0.05) were protective against malaria at the community level but not at the individual level. Paradoxically, the number of battle events since 1994 surrounding one's community was negatively associated with malaria risk (p < 0.0001). CONCLUSIONS: This research demonstrates the feasibility of using population-based behavioural and molecular surveillance in conjunction with DHS data and geographic methods to study endemic infectious diseases. This study provides the most accurate population-based estimates to date of where illness from malaria occurs in the DRC and what factors contribute to the estimated spatial patterns. This study suggests that spatial information and analyses can enable the DRC government to focus its control efforts against malaria.

Spatial and socio-behavioral patterns of HIV prevalence in the Democratic Republic of Congo.

This study uses a 2007 population-based household survey to examine the individual and community-level factors that increase an individual's risk for HIV infection in the Democratic Republic of Congo (DRC). Using the 2007 DRC Demographic Health Surveillance (DHS) Survey, we use spatial analytical methods to explore sub-regional patterns of HIV infection in the DRC. Geographic coordinates of survey communities are used to map prevalence of HIV infection and explore geographic variables related to HIV risk. Spatial cluster techniques are used to identify hotspots of infection. HIV prevalence is related to individual demographic characteristics and sexual behaviors and community-level factors. We found that the prevalence of HIV within 25 km of an individual's community is an important positive indicator of HIV infection. Distance from a city is negatively associated with HIV infection overall and for women in particular. This study highlights the importance of improved surveillance systems in the DRC and other African countries along with the use of spatial analytical methods to enhance understanding of the determinants of HIV infection and geographic patterns of prevalence, thereby contributing to improved allocation of public health resources in the future.

Local differences in human immunodeficiency virus prevalence: a comparison of social venue patrons, antenatal patients, and sexually transmitted infection patients in eastern kinshasa.

BACKGROUND: This study compares the sexual behavior and HIV prevalence of men and women at social venues where people meet new sexual partners in Eastern Kinshasa with that of sexually transmitted infection (STI) treatment and antenatal clinic (ANC) patients in the same area. METHODS: ANC patients, STI clinic patients, and social venue patrons were interviewed, asked to provide a blood sample on-site, and provided with information about obtaining test results. Every patron at identified social venues in the study area was invited to participate. RESULTS: One thousand one hundred sixteen pregnant women; 66 male and 229 female STI clinic patients; and 952 male and 247 female patrons of social venues were interviewed and tested for HIV. HIV prevalence differed by group: ANC patients (4%); female venue patrons (12%); female STI patients (16%); male venue patrons (2%); and male STI patients (23%). HIV prevalence among sex workers at social venues (29%) was higher than HIV prevalence among other female patrons with new or multiple partnerships in the past four weeks (19%) and higher than HIV prevalence among female patrons denying sex work (6%). However, the absolute number of infected women was higher among women reporting recent new or multiple partnerships than among the smaller group of sex workers (23 vs. 18). Two-thirds of the infected female STI patients (24/36) reported no more than one and no new sexual partner in the past year. CONCLUSION: Improving prevention programs in Kinshasa is essential. Prevention efforts should not neglect women at social venues who do not self-identify as sex workers but who have high rates of new sexual partnership formation.

Free distribution of insecticide treated bed nets to pregnant women in Kinshasa: an effective way to achieve 80% use by women and their newborns.

OBJECTIVE: To determine whether long lasting insecticide treated bed nets (LLINs) distributed free of charge to pregnant women at their first antenatal clinic visit in Kinshasa, DRC are used from the time of distribution to delivery and 6 months after delivery. METHODS: Women were enrolled into a cohort study at their first antenatal care (ANC) visit and provided LLINs free of charge. Reported use of these nets was then measured at the time of delivery (n = 328) and in a random sample of women (n = 100) 6 months post-delivery using an interviewer administered, structured questionnaire. RESULTS: At baseline, only 25% of women reported having slept under a bed net the night before the interview. At the time of delivery, after being provided an LLIN for free, this increased to 79%. Six months post-delivery (n = 100), 80% of women reported sleeping under a net with a child under the age of 5 the night before the interview. CONCLUSIONS: Freely distributed bed nets are acceptable, feasible and result in high usage. Free distribution of bed nets during antenatal clinic visits may be a highly effective way to rapidly increase the use of bed nets among both pregnant women and their newborn infants in areas with high levels of ANC attendance.